A collection of reverse-engineered documentation for the instruction sets for various generations of Mali GPU's. This is mostly my own work, and since it is not "official," there may be inaccuracies, missing things, etc.
Documentation for Bifrost is here.
Documentation for Midgard here.
Utgard wasn't a unified architecture, so there are two completely different engines for vertex shaders and fragment shaders, the former called the GP and the latter the PP. Documentation for the GP is here and documentation for the PP is here.